Abstract: A safety syringe is provided which includes a housing and a barrel mounted for reciprocating movement within the housing. A ring is mounted to the barrel and is rotatable relative to the housing and to the barrel. The ring includes a plurality of tabs circumferentially spaced from each other. An interior wall of the housing includes a plurality of ramps and a plurality of stops. The ramps cooperate with the tabs of the ring so as to rotate the ring relative to the housing and to the barrel, while the stops cooperate with the tabs for stopping the rotation of the ring relative to the housing and to the barrel. Locking means is also included within the interior wall of the housing for locking the barrel so as to allow for only a single use of the safety syringe.